There is known a differential transmission system configured to transmit a differential signal pair including opposite-phase signals respectively to two signal lines forming a pair. This differential transmission system has a feature in that the data transmission speed can be increased, and hence is practically used in various fields in recent years.
For example, when the differential transmission system is used for data transmission between an apparatus and a liquid crystal display, the apparatus and the liquid crystal display each include a DisplayPort connector designed in conformity with the DisplayPort standard. As the DisplayPort standard, there are known Video Electronics Standard Association (VESA) DisplayPort standard 1.0 and Version 1.1a thereof.
This DisplayPort connector is one type of a differential signal connector, and has a first connection side configured to connect to a connection counterpart, and a second connection side configured to connect to a printed board of the apparatus or the liquid crystal display. The form of the first connection side is strictly determined by the DisplayPort standard due to the relationship with the connection counterpart, but the form of the second connection side is relatively free. This type of differential signal connector is disclosed in Patent Document 1.
The connector of Patent Document 1 includes, as illustrated in FIG. 26, two sets of signal contacts 121 arranged in pairs as a lower contact group constructing the connector, and ground contacts 122 arranged on both sides of each set of the signal contacts 121.
Further, on the first connection side, as illustrated in FIG. 26, contact portions 121a of the signal contacts 121 and contact portions 122a of the ground contacts 122 are arranged in a row at predetermined intervals D1.
On the other hand, on the second connection side, as illustrated in FIG. 26, terminal portions 121b of the signal contacts 121 are arranged in a first row R1, and terminal portions 122b of the ground contacts 122 are shifted to be arranged in a second row R2.
With this arrangement, an interval D2 between the terminal portions 121b and 122b is larger than the interval D1 between the contact portions 121a and 122a. Thus, while downsizing the connector, it is intended to secure the mountability of the terminal portions 121b and 122b into through holes (not shown) requiring a certain size and arrangement at certain interval.